fs/xfs/xfs_bmap_item.h

   1 /*
   2  * Copyright (C) 2016 Oracle.  All Rights Reserved.
   3  *
   4  * Author: Darrick J. Wong <darrick.wong@oracle.com>
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version 2
   9  * of the License, or (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it would be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU General Public License
  17  * along with this program; if not, write the Free Software Foundation,
  18  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301, USA.
  19  */
  20 #ifndef __XFS_BMAP_ITEM_H__
  21 #define __XFS_BMAP_ITEM_H__
  22
  23 /*
  24  * There are (currently) two pairs of bmap btree redo item types: map & unmap.
  25  * The common abbreviations for these are BUI (bmap update intent) and BUD
  26  * (bmap update done).  The redo item type is encoded in the flags field of
  27  * each xfs_map_extent.
  28  *
  29  * *I items should be recorded in the *first* of a series of rolled
  30  * transactions, and the *D items should be recorded in the same transaction
  31  * that records the associated bmbt updates.
  32  *
  33  * Should the system crash after the commit of the first transaction but
  34  * before the commit of the final transaction in a series, log recovery will
  35  * use the redo information recorded by the intent items to replay the
  36  * bmbt metadata updates in the non-first transaction.
  37  */
  38
  39 /* kernel only BUI/BUD definitions */
  40
  41 struct xfs_mount;
  42 struct kmem_zone;
  43
  44 /*
  45  * Max number of extents in fast allocation path.
  46  */
  47 #define XFS_BUI_MAX_FAST_EXTENTS        1
  48
  49 /*
  50  * Define BUI flag bits. Manipulated by set/clear/test_bit operators.
  51  */
  52 #define XFS_BUI_RECOVERED               1
  53
  54 /*
  55  * This is the "bmap update intent" log item.  It is used to log the fact that
  56  * some reverse mappings need to change.  It is used in conjunction with the
  57  * "bmap update done" log item described below.
  58  *
  59  * These log items follow the same rules as struct xfs_efi_log_item; see the
  60  * comments about that structure (in xfs_extfree_item.h) for more details.
  61  */
  62 struct xfs_bui_log_item {
  63         struct xfs_log_item             bui_item;
  64         atomic_t                        bui_refcount;
  65         atomic_t                        bui_next_extent;
  66         unsigned long                   bui_flags;      /* misc flags */
  67         struct xfs_bui_log_format       bui_format;
  68 };
  69
  70 static inline size_t
  71 xfs_bui_log_item_sizeof(
  72         unsigned int            nr)
  73 {
  74         return offsetof(struct xfs_bui_log_item, bui_format) +
  75                         xfs_bui_log_format_sizeof(nr);
  76 }
  77
  78 /*
  79  * This is the "bmap update done" log item.  It is used to log the fact that
  80  * some bmbt updates mentioned in an earlier bui item have been performed.
  81  */
  82 struct xfs_bud_log_item {
  83         struct xfs_log_item             bud_item;
  84         struct xfs_bui_log_item         *bud_buip;
  85         struct xfs_bud_log_format       bud_format;
  86 };
  87
  88 extern struct kmem_zone *xfs_bui_zone;
  89 extern struct kmem_zone *xfs_bud_zone;
  90
  91 struct xfs_bui_log_item *xfs_bui_init(struct xfs_mount *);
  92 struct xfs_bud_log_item *xfs_bud_init(struct xfs_mount *,
  93                 struct xfs_bui_log_item *);
  94 void xfs_bui_item_free(struct xfs_bui_log_item *);
  95 void xfs_bui_release(struct xfs_bui_log_item *);
  96 int xfs_bui_recover(struct xfs_mount *mp, struct xfs_bui_log_item *buip);
  97
  98 #endif  /* __XFS_BMAP_ITEM_H__ */